Table 1 Comparison between the previous 0/4-hour protocol vs. the 0/1/4-hour OUT-ACS protocol
|  | Historical cohort (0/4-hour protocol) 2016–2018 [12] | OUT-ACS implementation study cohort 2023 | ||
|---|---|---|---|---|
Total n = 1711 | Total n = 995 | 0/1-hour rule-in/rule-out cases n = 676 | 0/1-hour observation group cases n = 319 | |
Female | 47.7% (n = 816) | 50.6% (n = 503) | 51.5% (n = 348) | 48.6% (n = 155) |
Age | 56 years (45–68) | 58 years (46–72) | 53 years (42–63) | 73 years (58–83) |
Symptom onset to arrival | 3.8 h (1.5–12.4) | 4.2 h (1.5–17.6) | 4.1 h (1.5–18.3) | 4.4 h (1.6–16.4) |
Arrival to first blood draw | 2.1 h (1.5-3.0) | 2.6 h (1.8–3.7) | 2.6 h (1.8–3.7) | 2.6 h (1.8–3.6) |
Symptom onset to first blood draw | 6.6 h (4.0-14.8) | 7.8 h (4.6–20.4) | 7.8 h (4.5–21.7) | 7.8 h (4.8–18.9) |
Minutes between 0- and 1-hour sample | 65 min (60–70) | 63 min (60–66) | 63 min (60–66) | 63 min (60–65) |
Hours between 0- and 4-hour sample | 4.3 h (4.1–4.9) | 4.6 h (4.1–5.5) | 4.2 h (4.0-4.9)‡ | 4.6 h (4.1–5.6) |
Troponin assessment time | 9.5 h (7.7–13.5) | 7.0 h (4.1–11.6) | 6.0 h (3.9–10.0) | 9.3 h (5.8–15.7) |
Total LOS at the clinic | 11.9 h (9.8–16.1) | 9.9 h (6.8–14.8) | 9.0 (6.5–12.7) | 12.3 h (8.7–18.4) |
Diagnosed MI | 3.6% (n = 61)* | 2.0% (n = 20)†| n = 17 | n = 3 |